Method and device for collecting and testing for fecal occult blood

ABSTRACT

A method and device for collecting and testing fecal occult blood which permits multiple analyses of a single fecal sample. The device is a combination of a sampler for collecting the fecal matter and a test slide. The fecal sampler comprises a pocket-like wipe pad for obtaining direct anal stool smears. An insert is disposed in the pocket of the wipe pad. The slide has a profiled opening similar to the design of the wipe pad. This opening acts as a receptacle for the pad when the fecal smear is transferred to the guaiac specimen receiving sheet of the slide. When the slide is closed the insert can be removed from the wipe pad. This design permits an analysis to be done on the specimen receiving sheet of the slide together with a second confirmatory test for human hemoglobin on portions of the insert. The fecal material on the insert is physically removed from the guaiac specimen receiving sheet.

This invention relates to a oonvenient method and device for collectingand detecting occult blood in fecal matter. More particularly, thisinvention relates to a collection and test device that permits multipleanalyses of a single fecal sample. The device of this invention can beused to collect, transport and carry out a variety of analyses in asingle fecal sample at two different test sites of the device. Thedevice can be employed in the privacy of one's home and is convenientand aesthetic to use.

Specimen slides and procedures for detecting occult blood in fecalmatter are well known. Typically, in the case of a test for occult bloodin feces, a sample of fecal matter is smeared on the specimen test sheetwhich has been treated with guaiac. A developing solution, such as aperoxide solution, is applied to the opposite side of the sheet. Ifblood is present in the fecal matter, the guaiac reaction will color thepaper blue. This procedure is disclosed in U.S. Pat. No. 3,966,006.

One of the disadvantages associated with this test is that falsepositive results can occur, i.e., the positve result is not due to humanhemoglobin. For example, non-hemoglobin interfering substances in thefecal matter such as peroxidases, various foodstuffs, drugs, and animalheme, which can be a result of meat in the diet, can give a positiveresult. A still further disadvantage is the inconvenience of obtaining afecal sample from the toilet bowl.

Some of the above disadvantages may be minimized by the use ofimmunological tests which are specific for human hemoglobin. The enzymeimmuno assay (EIA) for the detection of human hemoglobin in feces isknown to the art. Briefly, the EIA test is a reaction between anantibody and an antigen (hemoglobin). The hemoglobin is reacted with aspecific anti-human hemoglobin antibody and attached to the solid phase.This antibody-antigen complex is then reacted with anti-human hemoglobinwhich is conjugated to alkaline phosphatase. The enzymatic activity ofthe resulting complex bound to the solid phase is then quantified. Acolor intensity is measured instrumentally and the absorbance isdirectly related to the amount of human hemoglobin (antigen) in thesample. A typical EIA assay for fecal human hemoglobin is disclosed inU.S. Pat. No. 4,427,769.

However, the EIA assay described above also has its disadvantages. Humanhemoglobin in fecal samples degrades with time. The degradation occurswith loss of antigenicity which results in falsely reduced values whenemploying the EIA assay. In brief, the immunoassay test specific forhuman hemoglobin requires that the hemoglobin retains its structuralintegrity. It has been discovered that guaiac is one component that hasa deleterious effect on the stability of human hemoglobin.

A known device and method for conducting an immunoassay for fecal humanhemoglobin is also disclosed in U.S. Pat. No. 4,427,769. In this device(Fecatest), the fluids from the fecal sample are passed through a guaiacimpregnated filter paper onto an absorbent material before conducting anEIA assay. The following studies were conducted after storing fecalsamples containing human hemoglobin in the Fecatest device.

Three fecal samples containing human blood were applied to and stored inthe Fecatest device up to nine days and then analyzed by FECA-EIALabsystems assay. The results, i.e., color intensity measured at anabsorbance of 405 nm are set forth below in Table 1.

                  TABLE 1                                                         ______________________________________                                        SAMPLE      R.T. STORAGE DURATION, DAYS                                       No.         0      1          3     9                                         ______________________________________                                        1           2.05   0.48       0.13  0.00                                      2           1.07   0.31       0.00  0.00                                      3           2.24   0.89       0.00  0.00                                      ______________________________________                                    

The above data clearly show the rapid degradation of hemoglobin withtime. Virtually no color is seen on Day 3 on all samples.

When the same fecal samples were applied to the sampling device of thepresent invention and stored up to nine days, a surprising improvementin the stability of hemoglobin was observed. The EIA kit supplied byLabsystems as noted above was also employed to analyze these samples.The results are set forth in Table 2.

                  TABLE 2                                                         ______________________________________                                        SAMPLE      R.T. STORAGE DURATION, DAYS                                       No.         0      1          3     9                                         ______________________________________                                        1           2.62   1.71       1.56  0.86                                      2           2.36   2.58       1.10  0.26                                      3           2.06   1.40       0.96  0.32                                      ______________________________________                                    

Color is visible in all samples even after 9 days of storage at roomtemperature.

It is thus desirable that samples analyzed immunologically for humanhemoglobin be protected from excessive contact with guaiac. The presentinvention minimizes guaiac contamination of the sample that may have tobe analyzed immunologically for human hemoglobin.

It is therefore an object of this invention to provide a testing deviceand method which minimizes the guaiac contamination of the fecal samplethat is to be analyzed immunologically for human hemoglobin.

It is a further object of this invention to provide a test device andmethod which permits the multiple analyses of a single fecal sample attwo different test sites on the device.

It is an additional object of this invention to provide a test deviceand method for testing fecal occult blood which permits a convenient andaesthetic manner for collecting and transferring the fecal sample to thedifferent test sites on the device.

Briefly, this invention consists of an improved test device for fecaloccult blood which comprises two components. The first component is afecal sampler employed to collect the fecal matter by direct wiping orpatting of the anal area. The sampler is a combination of a pocket-likemember and an absorbent insert which is retained within the pocket. Thepocket is made of a soft paper having the consistency similar to toilettissue and functions as a wipe pad.

The second component is a test slide having a guaiac treated specimenreceiving sheet between a front panel and a rear panel with openings ineach of the panels and pivotal covers to cover these openings, similarto the slide described in U.S. Pat. No. 3,996,006. This slide receivesand retains the fecal sampler. The sampler is placed fecal smear sidedown in contact with the specimen receiving sheet. The sheet is borderedby a profiled aperture formed within the slide which resembles the wipepad. The design is such that when the wipe pad is positioned within theaperture, and the front cover closed, a portion of the insert disposedin the wipe pad is exposed beyond the closure line of the cover. Thisenables one to withdraw the absorbent insert from the wipe pad pocketwith the cover remaining closed. The insert which absorbs the fecalfluid from the wipe pad can be sectioned for a confirmatory assay suchas an immunological assay. Thus, in one single collection and action,two separate membranes receive the fluids of the fecal sample and can beindividually and independently tested. The guaiac sheet can be testedwith a peroxide developing solution and the absorbent insert which isfree of guaiac can be subjected to a confirmatory EIA assay.

A detailed description and better understanding of this invention can behad by referring to the accompanying drawings which show a preferredembodiment of the present invention.

FIG. 1 is a perspective view of a packaged test device of thisinvention;

FIG. 2 is a perspective view of the packaged testing device of FIG. 1having been opened prior to use and showing the components of thisinvention contained therein;

FIG. 3 is an enlarged perspective view of the slide as viewed from therear, showing rear flap opened exposing the testing surface incuding thecontrol area;

FIG. 4 is a perspective view of the slide as viewed from the front in anopened mode about to receive a fecal sample to be tested;

FIG. 5 is a perspective view of the testing device in a closed modeprior to testing as viewed from the front;

FIGS. 6 and 7 are top and underside plan views respectively of blanksprior to folding, for preparing a slide in accordance with thisinvention;

FIG. 8 is a perspective view of the rear panel of the slide showing adeveloping solution being applied to the testing surface including thecontrol area;

FIG. 9 is a perspective view of a modified slide demonstrating optionalmeans to close the slide;

FIG. 10 is a perspective view of one form of the absorbent insertshowing fecal stains and about to be cut in strips for additionaltesting;

FIGS. 11A-11C are perspective views illustrating other embodiments forthe absorbent insert;

FIG. 12 is a perspective view illustrating a test strip obtained fromthe absorbent insert being placed in a tube containing reagentspreparatory for EIA testing for human hemoglobin.

Referring to FIG. 1 and FIG. 2, a pre-packaged testing device 10 has atear off strip 12 on one edge of the package. The contents of thepackage test slide 14, wipe pad 16, and absorbent insert 18 are shown inFIG. 2. The testing area of the slide is revealed when flap 22 of rearpanel 20 is opened. Between front panel 40 and the rear panel a specimenreceiving sheet 26 is placed as viewed in insert 24. A portion of thesheet has a control area 28 which has a positive monitor 30 and anegative monitor 32. The appearance of the slide about to receive afecal sample is shown in FIG. 4. It will be noted the front panel of theslide has a cover 34 which contains an adhesive strip 36 and a contactadhesive zone 44. The front panel has a profiled aperture 42 whichresembles the design of wipe pad 16 and serves as a receptacle for thewipe pad which contains fecal sample 50. The wipe pad is a component offecal sample 17 which also comprises the absorbent insert 18 containedwithin the wipe pad.

As illustrated in FIG. 5, after the fecal sample has been transferred tothe slide and the front cover is closed, a portion of the insert isexposed beyond the closure line of the cover. It will be noted that theadhesive strip overlies the wipe pad and does not contact the insert.This permits the insert to be slidably withdrawn from the wipe pad withthe cover maintained in a closed position.

To form the slide as shown in FIGS. 3 and 4, the panels of the blanksviewed in FIGS. 6 and 7 are folded and bonded together by adhesive bonds52. These blanks comprise paper or cardboard.

A modification of the slide 14A is shown in FIG. 9 wherein the profiledaperture 42 is bonded by a contact adhesive 60. The wipe pad in thiscase has a wider border 16' which enables the pad to contact adhesive 60when transferred to the slide. In this manner the wipe pad is bonded tofront panel 40 and the pad insert 18 is free to be slidably removed fromthe pad when the cover 34 is closed. Additional adhesive zones 62centrally located on the sides of the front panel 40 permit a firmbonding the cover to the panel.

To use the slide, the patient separates cover 34 from panel 40. A fecalsample 50 is collected by direct wiping or patting of the anal area withthe wipe pad portion 16 of sampler 17 after defecation. This isaccomplished in the same manner as one would use toilet tissue. Thefecal sampler with the smear side down is placed in contact with thespecimen receiving sheet 26 which is bordered by a profiled aperture 42.The profile resembles the design of the wipe pad and serves as areceptacle for the pad. The peel off cover of adhesive strip 36 isremoved and slide cover 34 is closed by bonding it to panel 40. Thepatient returns the slide either to his physician or a laboratory foranalysis. The physician or technician removes absorbent insert 18 whichwas housed within wipe pad 16 as illustrated in FIG. 5. The insert isset aside while the guaiac test is developed. The physician ortechnician then pulls flap 22 free of panel 20 and opens it outwardly asviewed in FIG. 8. Through the opening thus made a developing solution38, such as hydrogen peroxide, is applied to the receiving sheet 26 atstained area 54. The developing solution is also added to control area28 to cover positive and negative monitors 30 and 32. The results arethen observed, i.e., a blue color denotes a positive test.

If the guaiac test is positive, the insert which was set aside is usedto conduct a second confirmatory test, such as an immunological testspecific for human hemoglobin. The insert, which is free of guaiac, canbe cut into strips 70 or have discs 76 punched out. As noted in FIG. 12a strip 90 can be placed in tube 92 containing reagent 94 to elute fecalmatter 70' for an EIA assay.

The main advantage of this invention, therefore, is that in one singlecollection and action two separate membranes, i.e., the specimenreceiving sheet and the absorbent insert, receive the components of thefecal sample and can be individually and independently tested. The fecalmatter is placed in direct contact with the specimen receiving sheetwhich contains guaiac. The fluid from the fecal sample passes throughthe wipe pad and is collected on the insert which is free of guaiac.This design permits for both the standard test for fecal occult bloodwhich depends on the hemoglobin catalyzed oxidation of guaiac and aconfirmatory test such as an immunological assay specific for humanhemoglobin in which the fecal sample should be relatively free of anycontact with guaiac. Further, these tests can be conducted withoutdisturbing or removing the fecal matter from the slide.

Another advantage of the device of this invention is that theconstruction is not air-tight and enough absorbent material is providedso that drying and aeration of the sample is facilitated. This isnecessary to minimize microbial growth that may further degradehemoglobin or other analytes of interest. Known sampling and testingdevices that are kept tightly closed do promote growths of black andmoldy spores.

A still further advantage of the sampling and testing device of thisinvention is that the test kit can include more than one fecal samplerper test. Any accidental loss of the wipe pad samples does not destroythe utility of the device. In the event that an adequate sample is notobtained in one wiping, one merely throws away the inexpensive wipe padand tries another pad.

This invention also permits improved sample selection. The technician ispresented with a relatively big absorbent insert containing the fecalcomponents for an EIA assay. The technician is able to view theabsorbent insert and punch out samples for EIA assay from areas ofhighest fecal concentration, i.e., the most stained areas. Such aselection is not possible with prior art devices where pre-cut discsabsorb whatever amount of fecal fluid that comes through a guaiaccontaining membrane.

The above embodiments are illustrative and are not intended to belimiting.

What is claimed is:
 1. A device for collecting and testing fecal occultblood comprising in combination:(a) a fecal sampler comprising a wipepad and an insert retained therein; (b) a test slide comprising a frontand rear panel, said front panel having means defining at least oneaperture, said aperture being profiled to receive the wipe pad having asimilar contour, sheet means carrying a test reagent between the frontand rear panel for the reception of a fecal specimen, a hinged cover,having an open position and a closed position, to overlie a portion ofthe front panel and said aperture when in said closed position and flapmeans in the rear panel opposite said aperture and pivotable to exposethe underside of the sheet, adhesive means positioned to contact andseal the wipe pad within said aperture when the cover is in said closedposition whereby the insert which has a portion exposed beyond theclosure line of the closed cover can be slidably removed from the sealedpad.
 2. The device of claim 1 wherein the test reagent is guaiac.
 3. Thedevice of claim 1 wherein the adhesive means comprises a stripintermediate the hinged cover which contacts and seals the wipe pad whenpositioned within said aperture and when the cover is in said closedposition.
 4. The device of claim 1 wherein the adhesive means comprisescontact adhesive means surrounding the profiled aperture which contactsand seals the wiping pad when the pad is placed in the aperture.
 5. Amethod for determining the presence of fecal occult blood on a specimentest slide having a guaiac treated specimen receiving sheet between afront and rear panel with openings in the front and rear panels andpivotable covers to cover said openings which comprises:(a) obtaining afecal specimen by direct wiping of the anal area with a fecal samplerwhich comprises a wipe pad and an insert; (b) transferring said specimento the receiving sheet by placing the smear from the wipe pad in directcontact with the sheet; (c) closing the front cover of the test slidewhereby the wipe pad is secured in the front opening and the insert hasa portion exposed beyond the closure line; (d) removing the insert whichcontains fecal fluids which passed through the wipe pad from the feces;(e) opening the rear cover and applying a developing solution to theguaiac sheet at the corresponding opening in the rear panel, and if thetest is positive, (f) conducting a second confirmatory test specific forhuman hemoglobin on said insert, said.sampler being free of guaiac.
 6. Amethod for determining the presence of fecal occult blood on a specimentest slide having a guaiac treated specimen receiving sheet between afront and rear panel with openings in the front and rear panels andpivotable covers to cover said openings which comprises:(a) obtaining afecal specimen by direct wiping of the anal area with a fecal samplerwhich comprises a wipe pad and an insert; (b) transferring said specimento the receiving sheet by placing the smear from the wipe pad in directcontact with the sheet; (c) closing the front cover of the test slidewhereby the wipe pad is secured in the front opening and the insert hasa portion exposed beyond the closure line; (d) removing the insert whichcontains fecal fluids which passed through the wipe pad from the feces;(e) opening the rear cover and applying a developing solution to theguaiac sheet at the corresponding opening in the rear panel; and (f)conducting a second confirmatory test specific for human hemoglobin onsaid insert, said sampler being free of guaiac.
 7. The method of claim 5in which the second confirmatory test is an immunological assay.
 8. Atest kit for collecting and testing fecal occult blood whichcomprises:(a) the device of claim 1, and (b) a developing solution whichreacts with said guaiac to color the sheet blue.